Production of aliphatic carboxylic acids



Patented Mar. 5, 1935 1,993,555

UNHTED STATES PATENT cmcs PRQDUCTION F ALIPHATIC CARBOXYLIC ACIDS Alfred '1. Larson, Wilmington, Del., assignor to E. I. du Pont de Nemours & Company, Wilnnngton, DeL, a corporation of Delaware No Drawing. Application November 15, 1932, Serial No. 642,765

1s Claims. (Cl. 260-112) This invention ate to t e y s of prior to the reaction. In many instances by organic compounds and particularly to the impregnating the charcoal with phosphoric, preparation of higher aliphatic acids by the sulphuric, arsenic, and like acids a good converinteraction of halogenated hydrocarbons, carbon sion is efiected; these latter catalysts may likemonoxide, and steam. wise be used in conjunction with a volatile halide. 5

An object of the present invention is to pro- In lieu of using the halogenated hydrocarbon Vide a process for the preparation of aliphatic per se a halogen and the proper hydrocarbon carboxylic acids from steam, carbon monoxide, may be used. For example, when acetic acid is and the halogenated hydrocarbons. A further to be prepared the reaction would be eilected by object of this invention is to provide a process interacting methane, chlorine, carbon monoxide, 10 for the preparation of monocarboxylic acids from and steam in the presence of activated charcoal. steam, carbon monoxide and halogenated hydro- If a higher acid is to be prepared the higher carbons in the presence of an absorbent material hydrocarbon, of course, should be employed. Such as pumice, silica gel, active Carbon, etc. When effecting the reaction in this manner a Another object of the invention is to provide a slight excess of the halogen over that required to process for the preparation of acids having the react with the hydrocarbon to form the halogen- St1116t1l1a1f0lmu1a ated hydrocarbon should be used, and in some R R instances the use of activating light rays, such as ultra-violet, will be found advantageous in initiating thereaction. 20

R R The halogenated hydrocarbons which are from steam, c rbo monoxide, and halogen suitable for reacting with the carbon monoxide substituted hydrocarbon, the R indicating hyand steam to form the d u e t e m n drogen or a substituted or unsubstituted similar and p yubstituted hydrocarbons. The haloor diss milar alkyl or aralkyl grouping, oth gen substituent thereof is preferably chlorine, 25 v objects and advantages will hereinafter appear. altho tho other halogens, min Ch orine and In accord with this invention aliphatic cariodine, may likewise be usedydr a b ns boxylic acids can be prepared from steam, care Containing a p y, econdary, or tertiary carbon monoxide, and a halogenated hydrocarbon hon t and that t v those yd by passing the tit t under t l carbons which are fully saturated with a halogen 3() pressure and temperature conditions, over an $11011 as Carbon etrachl ride, may be empl y d, absorbent material such as pumice, silica gel, but although I prefer use the ono-Substituted preferably over active carbon, and especially over derivatives of the hydlccdrbon- Examples of activated charcoal. The products resulting from the above halogenated e vat ves nc ude Such such a reaction will contain generally a mixture Compounds as methyl Chloride, ethyl chloride, 35 of aliphatic carboxylic acids some or" which have normal and D PY chlorides, l

a greater, some a lesser, number of carbon atoms pane, fia ethy 3- than are present in the hydrocarbon treated, an -p p r 2 -D p aliphatic acid containing one more carbon atom methylene Chloride, acetylene d ,D i y o e than the hydrocarbon, usually predominating.

Usually the presence of activated charcoal or triohloropropane, perchloroethano, n q v some other form of active carbon is sufficient to 1611i? hOmOlOgOllS halogenated yd ocarbons- AS effect a good conversion of the halogenated hyindicated above, the halogenated substituent of drocarbon to the acid. Under some circumthe above ed compounds m y n ain as well t h w v it may be found necessary in the other members of the elements or" the halogen 45 order to further the reaction to have another group rather than the Chlorine dic t dcatalyst present. A number of catalysts may b Raw materials suitable for use in the process used for this purpose and thos hi h h b are readily available from a number of sources. found particularly eilicient for effecting the Thus, t Carbon monoxide required for t e formation of acids from alcohols and carbon Syn hes s may easily be derived from various 50 monoxide are recommended, and particularly the Commercial Sources, Such for p W r halogens and volatile halides, such as chlorine, as, p u r s, carbide formation, t y bromine, hydrogen chloride, hydrogen bromide, liquefaction or other methods, and should be likeetc. with or without the presence of a metal Wise for the best results relatively P halide with which the charcoal may be saturated Inert ga h a nitrogen, m y be ncluded 55 chloride, chloroform, glyceryl chloride, 1:2:3- 40v Iii) with the reactants, this being advantageous in some cases from the standpoint of controlling the temperature of the exothermic reaction and of limiting the extent thereof, where it may be desired to restrict the overall conversion of the reactants for the sake of enhancing the relative yield of the desired acids.

The relative proportions of the reactants can be varied, although it has been found that very advantageous results are obtained when the steam and carbon monoxide are in excess with respect to the halogenated hydrocarbon. Concentrations of the latter within the range of from 1 to 10% by volume of the total reactants have been employed with good results.

The use of pressures in excess of atmospheric, say from 25900 atmospheres, is preferred. The reaction proceeds over a wide range of temperatures, altho the optimum temperature varies With specific cases, depending inter alia upon the hydrocarbon being used. Generally the desired reaction can be obtained at from 200 to 400 C. From the standpoint of practical operation the temperature should not be so low that the reaction rate is uneconomical nor so high as to resuit in undesirable by-products by decomposition and/or polymerization of raw materials. From this point of view the process has been found to operate satisfactorily at from 275 to 375 C.

The following examples will illustrate methods of practising the invention, altho the invention is not limited to the examples.

Example 1.-A gaseous mixture is prepared containing by volume carbon monoxide, and 5% isopropyl chloride, together with steam to give a steam: carbon monoxide and isopropyl chloride ratio of approximately 0.25. The resulting gaseous mixture is passed into a conversion chamber designed for carrying out exothermic gaseous reactions and in which activated charcoal is disposed. The temperature of the reaction is maintained at approximately 325 C. while the pressure is held at approximately 700 atmospheres. A good yield of isobutyric acid is obtained together with other organic compounds.

Example 2.A gaseous mixture is prepared containing by volume 95% carbon monoxide and 5% ethyl chloride, together with steam, to give a steam: carbon monoxide and ethyl chloride ratio of approximately .25. This gaseous mixture is reacted under the same pressure and temperature conditions as given under Example 1, the gases likewise passing over activated charcoal. Propionic acid is obtained.

The apparatus, which may be employed for conducting these reactions, may be of any conventional type and preferably one in which the temperature of exothermic reactions can be readily controlled at the desired value. Owing to the corrosive action of the acids produced, the interior of the converter and conduits leading therefrom should preferably be protected. This may be accomplished by using glass or glass-lined apparatus or by coating the inner surfaces of the apparatus with chromium or silver or using for the construction of this equipment acid-resisting alloys of, for example, molybdenum, cobalt, tungsten, chromium, copper, manganese, or nickel.

Various changes may be made in the method hereinbefore described without departing from the invention or sacrificing the advantages thereof.

I claim:

1. A process of producing aliphatic carboxylic acids which comprises reacting a halogenated aliphatic hydrocarbon and steam with carbon monoxide.

2. A process of producing aliphatic carboxylic acids which comprises reacting a halogenated aliphatic hydrocarbon and steam with carbon monoxide in the presence of a suitable absorbent material.

3. A process of producing aliphatic carboxylic acids which comprises reacting a halogenated aliphatic hydrocarbon and steam with carbon monoxide in the presence of active carbon.

4. The process which comprises reacting ethyl chloride, steam, and carbon monoxide and thereby producing propionic acid.

5. The process which comprises reacting propyl chloride, steam, and carbon monoxide, and thereby producing a butyric acid.

5. The process which comprises reacting a butyl chloride, steam, and carbon monoxide, and thereby producing a Valerie acid.

7. The process which comprises reacting propyl chloride, steam, and carbon monoxide, in the presence of active carbon and thereby producing a butyric acid.

8. The process which comprises reacting a butyl chloride, steam, and carbon monoxide, in the presence of active carbon and thereby producing a valeric acid.

9. The process which comprises reacting ethyl chloride, steam, and carbon monoxide in the presence of active carbon and thereby producing propionic acid.

10. A process of reacting a halogenated aliphatic hydrocarbon, steam, and carbon monoxide for the purpose of producing an aliphatic carboxylic acid, characterized in that the reaction is effected under a pressure within the range of 25900 atmospheres.

11. A process of reacting a halogenated aliphatic hydrocarbon, steam, and carbon monoxide for the purpose of producing an aliphatic carboxylic acid, characterized in that the reaction is effected at a temperature within the range of from 200-500 C.

12. A process of reacting a halogenated aliphatic hydrocarbon, steam, and carbon monoxide thereby producing an aliphatic carboxylic acid, characterized in that the reaction is effected in the presence of a volatile halide catalyst and a form of active carbon.

13. The process which comprises reacting a halogenated aliphatic hydrocarbon, steam, and carbon monoxide in the presence of a catalyst capable of promoting the synthesis of aliphatic acids from carbon monoxide and alcohols, and thereby producing an'aliphatic carboxylic acid.

' ALFRED T. LARSON. 

